Cover panels for walls, especially for siding applications

ABSTRACT

Molded or pressed cover panels for sidings of light weight material which have four reinforced borders with longitudinal grooves in their border end faces by means of which each panel is positioned at a fixed distance from the wall and keyed to adjacent panels by a key profile. The panels are individually suspended on their upper border on an anchoring grid by means of a nose connection and secured thereto by retaining buckles which engage one or more of the noses on the upper panel border.

United States Patent 11 1 1111 3,838,546 Tempes 14 1 Oct. 1, 1974 COVER PANELS FOR WALLS, 3,110,131 11/1963 leffress 52 235 x ESPECIALLY FOR SIDING APPLICATIONS 3,453,793 7/1969 Salton 1 52/586 X 3,530,633 9/1970 Scott 52/235 X {76] Inventor: Franz T mp Hll l 3 8 3,715,848 2/1973 Jordan 52/235 Munich 90, Germany [22] Filed: Jan. 8, 1973 Primary ExaminerPrice C, Faw, Jr. [21] Appl NO 321 578 Attorney, Agent, or FirmJ0seph A. Geiger ABSTR [30] Foreign Application Priority Data 5 3d d d T f d f r h o e or presse cover pane s or $1 ings 0 1g t Jan. 7, i972 Germany 54l weight material which have four reinforced borders 52 us. c1. 52/235 52/586 with longitudinal grooves in their border end faces by 51 Int. Cl Eli4b 2/88 means 0f which each Panel is PShihed fixed [58] Field of Search 52/235 586 585 487 lance from the Wall and keyed to adjacent Panels by 6 key profile. The panels are individually suspended on their upper border on an anchoring grid by means of a [56] References Cited nose connection and secured thereto by retaining buckles which engage one or more of the noses on the UNITED STATES PATENTS upper panel borden 2,027,882 l/l936 Ross 1. 52/235 X 2,129,441 9/1938 Otto 52/586 X 16 Claims, 9 Drawing Figures PAIENTEDbm mu smaor FIG. 8

FIG. 7

////////vv i IM/VHA/ m 5 04 V COVER PANELS FOR WALLS, ESPECIALLY FOR SIDING APPLICATIONS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cover panels for walls, and in particular to cover panels for use in siding applications on exposed building walls.

2. Description of the Prior Art It is generally desirable, in connection with wall coverings such as siding for outside walls, to use light weight cover panels which can be conveniently attached to the wall. Such, a siding protects the wall against weather influences and may also serve to give the wall a different color and/or visual aspect.

In the recent past it has become known to use plastic panels for this type of siding application. These panels have to be nailed to a lath grid of impregnated wood which is anchored on the building wall. This type of attachment has the disadvantage that the plastic panels have to be in a particular alignment in relation to the lath grid, and it has the additional shortcoming that the nails which are used for the attachment of the panels are visible and exposed to the weather. The latter may cause corrison of the nails.

SUMMARY OF THE INVENTION It is the primary objective of the present invention to overcome the above-mentioned shortcomings. The invention proposes to attain this objective by suggesting a novel cover panel which permits easy installation on the wall to be covered, and where the fastening elements used for this purpose are not visible from the outside and therefore not exposed to the influence of the weather.

The present invention suggests in particular that the novel cover panel is provided with reinforced panel borders on its four sides, of which at least the upper panel border and the lower panel border include a vertically oriented groove as part of the interlocking means between adjacent panels. A lower anchoring member which is attached to the wall includes an upstanding ledge whichis arranged to engage the longitudinal groove in the lower panel border, while an upper anchoring member positions the upper panel border by supporting the latter vertically and horizontally against the wall. For this purpose, the ledge between the upper longitudinal groove and the panel edge near the wall includes longitudinally spaced overhanging noses and interruptions in the ledge between these noses. A horizontal retaining buckle on the upper anchoring member is so arranged that it embraces' at least one of the noses, thereby providing the horizontal hold for the cover panel, while the weight of the latter is supported by the nose resting on the anchoring member.

One of the advantages of the structure of this invention lies in its low cost. Another advantage is the fact that the installation of these panels is very simple. A third advantage is the arrangement of the metallic fastener elements, which are not visible from the outside and which are therefore not exposed to the corroding influence of the weather.

According to a preferred embodiment of the invention, the structure of the earlier mentioned upper panel border is so that its profile is constituted by a continuous shoulder extending at a distance below the forward upper panel edge and a plurality of spaced, blockshaped or prismatic noses which extend upwardly from the shoulder, one vertical side of the noses forming the second flank of the longitudinal groove, while the opposite side of the nose forms an overhang configuration with a horizontal abutment face which cooperates with the upper anchoring member. This arrangement has the advantage of a very simple design which isinexpensive in mass production.

A further advantageous feature of the invention suggests that the retaining buckle for the upper panel border is itself conveniently insertable into the-anchoring member. This arrangement offers the advantage of a further simplification of the installation procedure. A preferred way of providing this insertion feature is the arrangement of a downwardly extending ledge along the inner border of the retaining buckle and a matching longitudinal vertical groove in the anchoring member. The ledge of the retaining buckle is then simply slid into the groove of the anchoring member. An alternate advantageous feature of the invention provides that the retaining buckle is attached to the anchoring means by means of a nail. This makes it possible to use a very simple, inexpensive retaining buckle for the attachment of the cover panels.

A still further advantageous feature of the invention suggests that the outer one of the two longitudinal ledges on opposite sides of the groove in the lower panel border is higher than the adjacent inner ledge. The purpose of this structure is to provide a so-called drip edge on the bottom of the cover panel which is useful in applications where the siding is exposed to rain. Such a drip edge prevents the penetration of water into the space between two adjacent cover panels and into the space between the siding and the wall itself.

In a preferred embodiment of the invention the cover panel further includes a key profile which is insertable in the longitudinal groove of the upper panel border. This key profile then serves as a connection for the horizontal positioning of the lower panel border of the next-higher cover panel. Any number of successive superposed cover panels can be keyed together in this manner in a very simple operation, whereby the upper panel border which is held in place vertically and horizonta-lly by a corresponding anchoring member and retaining buckle in each case positions the lower panel border of the next higher cover panel horizontally, while its vertical positioning is provided by its own upper noses. and anchoringmember. This arrangement permits the assembly of any number of rows of cover panels, one above the other, to provide a siding for a large wall area from a great number of much smaller cover panel units.

An additional feature of this preferred embodiment provides for a longitudinal groove in at least one of the lateral reinforced panel borders, including a vertical key profile which engages at least one of these longitudinal grooves. This offers the possibility of laterally interlockingadjacent cover plates into a continuous row of any length, by using a great number of comparatively narrow cover panel units.

The advantages of the two last-mentioned features of the invention can be still further enhanced by using a non-hardening putty to position the key profiles in their respective longitudinal grooves. This arrangement provides additional safety against the penetration of humidity or rain water between the cover panels.

A still further preferred feature of the invention is to fabricate these cover panels from plastic material or from asbestos. These materials have the advantage of a comparatively low weight combined with a good re sistance against weather influences and the absence of any need for maintenance or repairs.

The invention also suggests to fabricate the key profiles from either plastic material or asbestos. The earlier mentioned advantages apply here in a similar manner.

BRIEF DESCRIPTION OF THE DRAWINGS Further special features and advantages of the invention will become apparent from the description following below, when taken together with the accompanying drawings which illustrate, by way of example. several embodiments of the invention, represented in the various figures as follows:

FIG. 1 shows in a perspective view a cover panel embodying the invention as seen from its backside;

FIG. 2 shows an enlarged horizontal cross section through the cover panel of FIG. 1 taken along the line IIII of FIG. 1;

FIG. 3 shows an enlarged vertical cross section of the cover panel of FIG. 1 taken along line IlIlII of FIG. 1;

FIG. 4 shows an enlarged vertical cross section through a portion of a wall and an installed cover panel according to the invention;

FIG. 5 shows in a horizontal cross section taken along the line V'V in FIG. 4 a retaining buckle of the invention;

FIG. 6 shows the retaining buckle of FIG. 5 in a perspective view;

FIG. 7 shows in a vertical cross section similar to that of FIG. 4 a second embodiment of the invention using different anchoring means;

FIG. 8 shows in a partial vertical cross section a third embodiment of the invention with a further modified anchoring means; and

FIG. 9 shows in a perspective view the retaining buckle of the embodiments of FIGS. 7 and 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 is shown a cover panel 1 which embodies the present invention. The four sides of the rectangular outline of cover panel 1 are formed by reinforced upper and lower panel borders 41 and 51, and by similar lateral panel borders 21 and 31. These reinforced panel borders are shown in more detail in FIGS. 2 and 3. The central wall area or cover panel 1 is further stiffened by means of one vertical and two horizontal stiffening ribs 61 and 71. On the backside of the upper panel border (FIG. 1 and FIG. 3) are further provided several longitudinally spaced block-shaped noses 4.

These noses 4 are so arranged on the panel border that 1 they define a longitudinal groove profile 42 between them and an upstanding longitudinal ledge on the outer side of the upper panel border. This can best be seen I The lower panel border 51 and the two lateral panel borders 2] and 31 are provided with similar longitudinal grooves in the end face of the reinforced border profiles. In FIG. 2 are shown the two lateral longitudinal grooves 22 and 32, while FIG. 3 shows the earlier mentioned upper longitudinal groove 42 and a similar lower longitudinal groove 52 in the lower panel border 51. The cross section of the lower panel border differs somewhat from the other panel borders in that thetwo ledges l1 and 14 which enclose groove 52 between them are of different height, the outer ledge 11 being higher than the inner ledge 14. The specific purpose of this suggestion will be explained further below.

The cover panel 1 according to the invention further includes a retaining buckle which is designed to engage the upper panel border 41 by embracing at least one of the earlier mentioned noses 4 which project from that panel border. Such a retaining buckle 5 is shown in FIGS. 4 to 6. This retaining buckle 5 provides a horizontal link between the cover panel and a fixed anchoring member 17 which in turn is permanently attached to the building wall 15 (FIG. 4). The lower panel border 51 of the cover panel 1 is similarly positioned horizontally by means of a lower retaining member 8 which includes an upstanding ledge 10 capable of engaging the lower longitudinal groove 52 of panel 1. The lower retaining member 8 is permanently attached to another anchoring member 16 by means of a nail 18. The earlier mentioned retaining buckle 5 is likewise fastened to its anchoring member 17 by means of a nail 19.

The embodiment of FIG. 4 shows two anchoring members 16 and 17 in the form of simple lath profiles which are part of a lath grid. The drawing shows that the cover panel 1 is mounted on the lath profiles with its backside contacting the vertical lath face. It should be understood that this is not a necessary condition for this embodiment. In fact, it is advantageous to provide either a vertical gap between the backside of cover panel 1 and the anchoring members 16 and 17, or to provide spaced ventilation recesses in the anchoring members, especially in the lower anchoring member 16. The result is a so-called back-ventilated cover plate. As FIG. 4 clearly illustrates, the horizontal positioning of cover plate 1 relative to the anchoring elements 16 and 17 is fully determined by the retaining buckle 5 which engages the nose 4 of thee upper panel border, and by the retaining member 8 which engages the lower panel border, or, respectively, by the key profile 12 which locks the lower panel border of the next higher panel into the longitudinal groove 42 of the upper panel border 41. However, it should be noted that the supporting noses 4 on the upper panel border 41 must overlap the edge of the upper anchoring member 17 in order to assure the vertical positioning of the panel. In the case of a wooden lath grid as shown in FIG. 4, for example. the retaining buckle S and the lower retaining member 8 are fastened to their respective anchoring members 16 and 17 by a nail 18 or 19.

The plan view configuration of a retaining buckle 5 of the embodiment of FIG. 4 is illustrated in FIGS. 5 and 6. FIG. 5 further shows the manner in which the retaining buckle engages a nose 4 of the cover plate 1.

In FIG. 4 is also shown the lower portion of a second cover plate 1 which is mounted top-adjacent to the first cover plate. The two cover plates are identical in structure. However, in this arrangement the lower panel border 51 of the top-adjacent cover plate is not independently positioned by a retaining member 8, as is the first cover plate. but it is keyed in a simple manner to the upper panel border 41 of the first cover plate. This is achieved by means of a flat upstanding key profile 12 whose lower edge engages the longitudinal groove 42 in the upper panel border 41 of a first panel. and whose upper edge engages the aligned longitudinal groove 52 of the lower panel border 51 of the upper panel 1. In order to provide independent vertical support for each cover panel 1, a gap 13 is provided between the opposing outer ledges of the upper panel border 41 and of the lower panel border 51 of the top-adjacent cover panel. The size of gap 13 is preferably between two and ten millimeters. It is further suggested that the key profile 12 is preferably stabilized in the longitudinal grooves by means of a non-hardening putty 43.

In FIG. 7 is illustrated a second embodiment of a cover panel arrangement according to the invention. Whereas the previously described arrangement (FIG. 4) suggested anchoring members 16 and 17 of impregnated wood attached to the wall in the manner of a lath grid, the arrangement of FIG. 7 suggests an alternative anchoring mode in which the cover panels 1 are attached to metallic anchoring members 7 and 9 which may be of aluminum, for example. It should be noted, however, that it might be preferable in certain cases to make the anchoring members 7 and 9 of plastic materials. The lower anchoring member 9 is comparable to the earlier described lower retaining member 8 of FIG. 4 and has a similar upstanding ledge 10 with which it engages the lower longitudinal groove 52 of the lower panel border 51 (FIG. 3). Thus, the lower anchoring member 16 and lower retaining member 8 of FIG. 4 are combined in FIG. 7 in a single anchoring member 9. Though the structure of the cover panel 1 itself is shown unchanged from the first embodiment of FIG. 1, the anchoring arrangement at its upper panel border 41 is quite different from that of the first embodiment. The upper anchoring member 17 is replaced by an anchoring profile 7 which includes a narrow longitudinal retaining groove whose flanks are parallel to the wall 15. This anchoring profile 7 cooperates with a retaining buckle 6 which includes a matching downwardly extending retaining ledge (see FIG. 9) which, when engaged in the groove of anchoring profile 7, produces a firm horizontal lock between the upper panel border 41 and the anchoring profile 7. As in the earlier embodiment, the retaining buckle 6 engages the nose 4 on the upper panel border 41 with a matching rectangular re cess. This arrangement offers a particularly simple assembly procedure in that the retaining buckle 6 is merely inserted vertically over the nose 4 into the retaining groove of the anchoring profile 7. The previously required nailing operation (nails 18 and 19 of FIG. 4) is thus eliminated.

The earlier described direct connection between the upper panel border 41 of a first cover panel 1 and the lower panel border 51 of a top-adjacent second cover panel 1 by means of a key profile 12 is shown unchanged in the embodiment of FIG. 7. As in the previous case, the key profile 12 is again preferably retained in its grooves by means of a non-hardening putty 43.

In FIG. 8 is shown a modification of the embodiment of FIG. 7. The modified anchoring profile 7' of this arrangement permits a very close positioning of the cover panel 1 in relation to the wall 15. A correspondingly narrowed, but otherwise unchanged lower anchoring member (not shown) would be used in this arrangement. All the other elements of this embodiment remain identical with those shown in the embodiment of FIG. 7. It should be understood that the advantageous feature of back-ventilation may also be provided in connection with the embodiments of FIG. 7 and FIG. 8 by means of longitudinal interruptions in the lower anchoring member 9 and in the upper anchoring profile 7, or by means of ventilation holes in these profiles.

A particularly advantageous feature of the embodiments of FIGS. 7 and 8 resides in the possibility of laterally shifting the cover panel 1 along its anchoring members. Thus, a succession of cover panels can simply be hanged into the anchoring grid and then shifted sideways to their final positions. The ledge of the retaining buckle 6 then slides in the retaining groove of the anchoring profile 7, and the lower panel border 51 slides along the ledge 10 of the lower anchoring member 9.

As mentioned earlier. the cover panel 1 of the various embodiments has on its lower reinforced border 51 ledges 11 and 14 of unequal height on opposite sides of the longitudinal groove 52. The purpose of this structure is to provide the outer bottom edge of the cover panel 1 with a so-called drip edge for rain water which may fall on the panel. This drip edge also prevents the water from penetrating between vertically adjacent cover panels into the space between the latter and the wall. An additional advantage of this type of drip edge is that it covers the lower anchoring member 8 or 9, respectively, making it invisible from the outside.

While FIGS. 4, 7 and 8 show a connection between vertically adjacent cover panels by means of a key profile 12, it should be understood that a similar key connection is provided for between laterally adjacent cover panels. by simply inserting similar key profiles into the longitudinal grooves 22 and 32 of two adjacent panels. These grooves are similar to the longitudinal grooves of the upper and lower panel borders so that key profiles identical to the key profile 12 can be used for the lateral keying. Every cover panel of the invention can thus be keyed to adjacent cover panels on all four sides in a very simple assembly procedure. This arrangement makes it possible to assemble any number of panels in a single row. and to install any number of rows in vertical succession. Each cover panel is nevertheless individually supported by its nose 4 and held at a fixed horizontal distance from the wall 15 by the anchoring members and retaining buckles. With the key profiles l2 firmly secured in their grooves by the aforementioned non-hardening putty 43, the siding thus produced is rattle-free, weather-sealed, maintenance free, and inexpensive in production and installation.

The individual cover panels may be made of plastic material in a simple molding procedure, or they may be made of asbestos for applications where the heat resistance of the material is of importance. The key profiles 12 may similarly be of plastic material or of asbestos. The use of plastic material makes it especially simple to provide any desired color coordination on the assembled siding.

What is claimed is:

l. A cover panel assembly for the protection of exposed building walls in the form of a siding application or the like, comprising in combination:

at least one generally rectangular cover panel whose outline is defined by an upper panel border, a lower panel border and two lateral panel borders;

an upper anchoring member adapted for permanent attachment to a building wall near the intended level of the upper panel border;

means defined by the upper panel border for vertically supporting the cover panel on the upper anchoring member;

means for horizontally retaining the upper panel border at a fixed distance relative to the upper anchoring member and the building wall; and

means for horizontally positioning the lower panel border at a fixed distance relative to the building wall.

2. A cover panel assembly as defined in claim 1,

wherein at least two cover panels are positioned above one another in an adjacent relationship; and

the horizontal positioning means for the lower panel border includes means for keying the lower panel border of the upper cover panel to the upper panel border of the lower cover panel.

3. A cover panel assembly as defined in claim 2,

wherein the lowermost of several vertically adjacent cover panels includes means for horizontally retaining its lower panel border, said retaining means including a lower anchoring member adapted for permanent attachment to a building wall near the intended level of the lower panel border. 4. A cover panel assembly as defined in claim 2, wherein the upper anchoring member has an upwardly oriented abutment face; and the vertical supporting means includes at least one overhanging supporting nose on the back of the upper panel border with a downwardly oriented face capable of engaging said abutment face of the upper anchoring member. 5. A cover panel assembly as defined in claim 4, wherein the horizontal retaining means of the upper panel border includes at least one upstanding generally prismatic retaining nose as an integral part of the upper panel border, and a separate retaining buckle which is arranged to engage the retaining nose so as to create a horizontal lock with the latter, the retaining buckle being further adapted for connection to the upper anchoring member. 6. A cover panel assembly as defined in claim 5, wherein the supporting nose of the vertical supporting means and the retaining nose of the horizontal retaining means are combined in the form of a generally prismatic nose block which overhangs the upper panel border toward the anchoring member. 7. A cover panel assembly as defined in claim 5, wherein the upper anchoring member for the cover panel is a lath member of generally rectangular cross section; and the retaining buckle has a generally flat body with an aperture for the retaining nose and is adapted for nailing to the upper face of the lath member. 8. A cover panel assembly as defined in claim 5, wherein the upper anchoring member for the cover panel has a profile which includes an upwardly open longitudinal groove; and the retaining buckle has an angular profile which includes a generally horizontal body portion with an aperture for the retaining nose and a vertical body portion which extends downwardly from the edge of the horizontal body portion in the area of the anchoring member so as to be insertable into the groove of the latter. 9. A cover panel assembly as defined in claim 6, wherein each cover panel further includes an upwardly open longitudinal groove in its upper panel border and an aligned downwardly open longitudinal groove in its lower panel border; and the keying means is in the form of at least one upstanding flat key profile which is adapted for insertion into the aligned upper and lower border grooves of vertically adjacent cover panels so as to horizontally position one relative to the other. 10. A cover panel assembly as defined in claim 9, wherein the keying means further includes a non-hardening putty for the stabilization of the key profilein the grooves of the panel borders. 7 11. A cover panel assembly as defined in claim 9. wherein the longitudinal groove in the upper panel border is defined by the spaced parallel vertical faces of the prismatic nose block and by an upstanding ledge on the front side of the upper panel border. 12. A cover panel assembly as defined in claim 9, wherein the longitudinal groove in the lower panel border is defined by the spaced vertical faces of two down wardly extending ledges, viz. a longer ledge at the front side of the lower panel border and a shorter ledge at the back side of the panel border. 13. A cover panel assembly as defined in claim 9, wherein the cover panels and the key profiles are of plastic material. 14. A cover panel assembly as defined in claim 9, wherein the cover panels and the key profiles are of asbestos.

15. A cover panel assembly as defined in claim 1,

' wherein at least two cover panels are positioned side by side in a row; and

the cover panels further include aligned longitudinal grooves in at least one lateral panel border and flat key profiles which are adapted to engage these longitudinal grooves so as to position the lateral panel borders of horizontally adjacent cover panels relative to each other.

16. A cover panel assembly as defined in claim 1,

wherein the four panel borders defining the outline of the cover panel are reinforced in comparison to the remaining area of the cover panel, the panel further including on its back side a grid of ribs for improved panel stiffness. 

1. A cover panel assembly for the protection of exposed building walls in the form of a siding application or the like, comprising in combination: at least one generally rectangular cover panel whose outline is defined by an upper panel border, a lower panel border and two lateral panel borders; an upper anchoring member adapted for permanent attachment to a building wall near the intended level of the upper panel border; means defined by the upper panel border for vertically supporting the cover panel on the upper anchoring member; means for horizontally retaining the upper panel border at a fixed distance relative to the upper anchoring member and the building wall; and means for horizontally positioning the lower panel border at a fixed distance relative to the building wall.
 2. A cover panel assembly as defined in claim 1, wherein at least two cover panels are positioned above one another in an adjacent relationship; and the horizontal positioning means for the lower panel border includes means for keying the lower panel border of the upper cover panel to the upper panel border of the lower cover panel.
 3. A cover panel assembly as defined in claim 2, wherein the lowermost of several vertically adjacent cover panels includes means for horizontally retaining its lower panel border, said retaining means including a lower anchoring member adapted for permanent attachment to a building wall near the intended level of the lower panel border.
 4. A cover panel assembly as defined in claim 2, wherein the upper anchoring member has an upwardly oriented abutment face; and the vertical supporting means includes at least one overhanging supporting nose on the back of the upper panel border with a downwardly oriented face capable of engaging said abutment face of the upper anchoring member.
 5. A cover panel assembly as defined in claim 4, wherein the horizontal retaining means of the upper panel border includes at least one upstanding generally prismatic retaining nose as an integral part of the upper panel border, and a separate retaining buckle which is arranged to engage the retaining nose so as to create a horizontal lock with the latter, the retaining buckle being further adapted for connection to the upper anchoring member.
 6. A cover panel assembly as defined in claim 5, wherein the supporting nose of the vertical supporting means and the retaining nose of the horizontal retaining means are combined in the form of a generally prismatic nose block which overhangs the upper panel border toward the anchoring member.
 7. A cover panel assembly as defined in claim 5, wherein the upper anchoring member for the cover panel is a lath member of generally rectangular cross section; and the retaining buckle haS a generally flat body with an aperture for the retaining nose and is adapted for nailing to the upper face of the lath member.
 8. A cover panel assembly as defined in claim 5, wherein the upper anchoring member for the cover panel has a profile which includes an upwardly open longitudinal groove; and the retaining buckle has an angular profile which includes a generally horizontal body portion with an aperture for the retaining nose and a vertical body portion which extends downwardly from the edge of the horizontal body portion in the area of the anchoring member so as to be insertable into the groove of the latter.
 9. A cover panel assembly as defined in claim 6, wherein each cover panel further includes an upwardly open longitudinal groove in its upper panel border and an aligned downwardly open longitudinal groove in its lower panel border; and the keying means is in the form of at least one upstanding flat key profile which is adapted for insertion into the aligned upper and lower border grooves of vertically adjacent cover panels so as to horizontally position one relative to the other.
 10. A cover panel assembly as defined in claim 9, wherein the keying means further includes a non-hardening putty for the stabilization of the key profile in the grooves of the panel borders.
 11. A cover panel assembly as defined in claim 9, wherein the longitudinal groove in the upper panel border is defined by the spaced parallel vertical faces of the prismatic nose block and by an upstanding ledge on the front side of the upper panel border.
 12. A cover panel assembly as defined in claim 9, wherein the longitudinal groove in the lower panel border is defined by the spaced vertical faces of two downwardly extending ledges, viz. a longer ledge at the front side of the lower panel border and a shorter ledge at the back side of the panel border.
 13. A cover panel assembly as defined in claim 9, wherein the cover panels and the key profiles are of plastic material.
 14. A cover panel assembly as defined in claim 9, wherein the cover panels and the key profiles are of asbestos.
 15. A cover panel assembly as defined in claim 1, wherein at least two cover panels are positioned side by side in a row; and the cover panels further include aligned longitudinal grooves in at least one lateral panel border and flat key profiles which are adapted to engage these longitudinal grooves so as to position the lateral panel borders of horizontally adjacent cover panels relative to each other.
 16. A cover panel assembly as defined in claim 1, wherein the four panel borders defining the outline of the cover panel are reinforced in comparison to the remaining area of the cover panel, the panel further including on its back side a grid of ribs for improved panel stiffness. 